The most common form of cancer in women in the United States is breast cancer, followed by lung cancer, cancer of the colon and rectum, uterine cancer, and ovarian cancer (see Table 2.3). The order of frequency of diagnosis of particular cancers varies somewhat across racial and ethnic groups. For example, although breast cancer is the most commonly diagnosed cancer for both white and black women, the second most frequently diagnosed cancer for black women is cancer of the colon and rectum and for white women lung cancer (American Cancer Society, 1997).
Risk factors have been identified that put women at greater risk for particular cancers (see Table 2.4). For most cancers, risk increases with age or with a family history of that type of cancer. In addition, however, there are behavioral factors, such as smoking, consumption of alcohol, or sexual history, that can increase the risk of cancer. In some cases, the association between a type of cancer and a risk factor is clear and well established (e.g., the link between smoking and lung cancer), in other cases, the data are less clear.
Much attention has been paid to possible increased risk of cancer among lesbians, particularly with respect to breast cancer. The assumption of higher risk for lesbians is based primarily on data from various studies suggesting that certain cancer risk factors occur at higher levels or with greater frequency in lesbians (Turner et al., 1992; White and Levinson, 1993). These factors include higher rates of smoking, alcohol use, poor diet, greater BMI, and differential rates of hormone exposure associated with less use of oral contraceptives and the lower likelihood of bearing children (Rankow, 1995a). To date, however, there are no epidemiological studies supporting a conclusion that lesbians are at increased risk for breast or other cancers.
There are several reasons for studying cancer among lesbians. For example, compared to heterosexual women, lesbians may have differences in risk factors, differences in prevalence of risk factors for each of the cancers, and differences in the way that health care is received (e.g., how